The Experts below are selected from a list of 1263 Experts worldwide ranked by ideXlab platform

Mario Gerla - One of the best experts on this subject based on the ideXlab platform.

  • Performance Comparison of Overlaid Bluetooth
    2013
    Co-Authors: Bluetooth Scatternet, Sewook Jung, Er Chang, Mario Gerla
    Abstract:

    Abstract- In a large scale Bluetooth network, scatternet is regarded as the only interconnection method among Piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. We propose Overlaid Bluetooth Piconets (OBP) to interconnect Piconets and form a virtual scatternet. Every piconet continuously changes its stages and collects metadata of Piconets in the communication range. If metadata shows existence of data to transfer, an inter-piconet connection is made and data is transferred. We compared throughput and efficiency of OBP with those of scatternet. Results show the feasibility of OBP usage instead of scatternet. I

  • new bluetooth interconnection methods overlaid bluetooth Piconets obp and temporary scatternets ts
    Computer Communications, 2007
    Co-Authors: Sewook Jung, A Chang, Mario Gerla
    Abstract:

    In a large scale Bluetooth network, the permanent Scatternet is regarded as the only method to interconnect Piconets. But, many Bluetooth devices do not support Scatternet. When they support it, features are limited. Moreover, in high mobility situations, the permanent Scatternet is not useful because of the extremely high overhead caused by frequent disconnections and reconnections. We propose Overlaid Bluetooth Piconets (OBP) and Temporary Scatternets (TS) to interconnect Piconets and form a virtual Scatternet. In OBP, every Piconet continuously changes its stages and collects metadata from Piconets within communication range. If metadata shows the existence of useful data to transfer, an inter-piconet connection is made and data is transferred. TS can be used instead of using permanent Scatternet to interconnect Piconets when needed. TS does not require large Scatternet formations and complex maintenance schemes. Moreover, it does not keep routing information. In this paper, we introduce and illustrate the OBP and TS concepts. We then compare throughput and efficiency of OBP and TS with respect to Scatternet.

  • video streaming over overlaid bluetooth Piconets obp
    Workshop on Wireless Network Testbeds Experimental evaluation & CHaracterization, 2006
    Co-Authors: Sewook Jung, A Chang, Mario Gerla
    Abstract:

    In a large scale Bluetooth network, scatternet has been regarded as the only interconnection method among Piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. Overlaid Bluetooth Piconets (OBP) interconnects Piconets and forms a virtual scatternet. This demo shows the possibility of using OBP instead of Scatternet for Video Streaming.

  • performance comparison of overlaid bluetooth Piconets obp and bluetooth scatternet
    Wireless Communications and Networking Conference, 2006
    Co-Authors: Sewook Jung, A Chang, Mario Gerla
    Abstract:

    In a large scale Bluetooth network, scatternet is regarded as the only interconnection method among Piconets. But, most Bluetooth devices do not support scatternet connection. Moreover, in high mobility situations, scatternet is not useful because of frequent disconnections and reconnections. We propose overlaid Bluetooth Piconets (OBP) to interconnect Piconets and form a virtual scatternet. Every piconet continuously changes its stages and collects metadata of Piconets in the communication range. If metadata shows existence of data to transfer, an inter-piconet connection is made and data is transferred. We compared throughput and efficiency of OBP with those of scatternet. Results show the feasibility of OBP usage instead of scatternet

  • bluetooth an enabler for personal area networking
    IEEE Network, 2001
    Co-Authors: Per Johansson, M Kazantzidis, Rohit Kapoor, Mario Gerla
    Abstract:

    We find ourselves today often carrying numerous portable electronic devices, such as notebook computers, mobile phones, PDAs, digital cameras, and mp3/MD/DVD players, used to help and entertain us in our professional as well as private lives. For the most part, these devices are used separately, and their applications do not interact. Imagine, however, if they could interact directly and thus create a network where information may flow seamlessly between the devices-such a network of personal devices is often referred to as a personal area network, or PAN. Moreover, access to the Internet via a (public) wireless LAN access point and/or via a 3G UMTS mobile phone would enable the PAN to be constantly online. The strongest candidate to provide the cheap short-range radio links necessary to enable such networks is the Bluetooth wireless technology. Seen from a networking perspective, a PAN will be expected to have participants, both of its "own" devices and "guest" devices from other PANs, continuously moving in and out of its coverage. To cope with this volatile nature of the network, the concept of ad hoc networking may be applied to create robust and flexible connectivity. A major technical step is taken when the Bluetooth piconet network architecture, a strict star topology, is extended into a scatternet architecture, where Piconets are interconnected. A consequence of creating scatternet-based PANs is that some nodes will form gateways between Piconets, and these gateways must be capable of time sharing their presence In each piconet of which they are members. While the Bluetooth standard defines the gateway nodes, the actual mechanisms and algorithms that accomplish the interpiconet scheduling (IPS) are left rather open. Given the lack of research literature in the subject, an overall architecture for handling scheduling in a scatternet is presented. A family of feasible IPS algorithms, referred to as rendezvous point algorithms, is also introduced and discussed.

Victor C M Leung - One of the best experts on this subject based on the ideXlab platform.

  • connection data rate optimisation of ieee 802 15 3 scatternets with multirate carriers
    International Journal of Sensor Networks, 2008
    Co-Authors: Zhanping Yin, Victor C M Leung
    Abstract:

    Designed for high rate Wireless Personal Area Networks (WPANs), the IEEE 802.15.3 Medium Access Control (MAC) protocol supports peer-to-peer communications in a piconet. In this paper, we analyse the link rate distribution of an 802.15.3 piconet employing multirate carriers at the physical layer, and show that the Expected Piconet Link Rate (EPLR) decreases gradually with the piconet radius. Furthermore, the Effective Scatternet Connection Rate (ESCR) is defined to minimise the stream connection cost in a scatternet by optimising the piconet coverage. Analytical and simulation results show that direct peer-to-peer communications in 802.15.3 Piconets bring a huge gain in the expected data rate of intra-piconet links. While the maximum piconet size minimises the number of Piconets in the scatternet and the number of hops for a randomly chosen connection, a medium sized piconet radius optimises the scatternet connection data rate. Thus, configuration of scatternets needs to consider the piconet size and channel reuse given the number of logical channels available.

  • connection data rate optimization of ieee 802 15 3 scatternets with multi rate carriers
    International Conference on Communications, 2006
    Co-Authors: Zhanping Yin, Victor C M Leung
    Abstract:

    The IEEE 802.15.3 MAC is designed for high data rate wireless personal area networks (WPANs), in which all communications within a piconet work in a peer-to-peer manner. In this paper, we analyze the link rate distribution of a piconet, and show that the expected piconet link rate for a UWB based 802.15.3 piconet decreases with the piconet radius. Furthermore, the effective scatternet connection rate is defined to optimize the piconet coverage within a scatternet. Analytical and simulation results show that the direct peer-to-peer communications in 802.15.3 bring a huge gain on the expected data rate of intrapiconet links, and a medium sized piconet radius optimizes the scatternet connection data rate given the number of logical channels available.

  • Third-Party Handshake Protocol for Efficient Peer Discovery and Route Optimization in IEEE 802.15.3 WPANs
    Mobile Networks and Applications, 2006
    Co-Authors: Victor C M Leung
    Abstract:

    Designed for high data rate wireless personal area networks, the IEEE 802.15.3 medium access control (MAC) protocol fits well with emerging technologies like ultra-wideband. Peer discovery is essential in 802.15.3 Piconets in which devices (DEVs) exchange MAC frames in a peer-to-peer manner. If two peer DEVs are unreachable, the standard peer discovery method will fail after unproductive backoff retransmissions, and a costly network layer routing is required. For DEVs uniformly distributed over the maximum coverage area of a piconet, such failures occur in up to 41.3% of intra-piconet peer discoveries. In this paper, we propose a novel third-party handshake protocol (3PHP) that provides more reliable and prompt peer discovery than the standard method. Especially, between directly unreachable DEVs within the same piconet, 3PHP replaces network layer routing by an efficient MAC layer forwarding that utilizes the available self-learning rate information to establish optimal routes. The mean peer discovery time for 3PHP is 100 μs lower than the standard method between directly reachable DEVs. More significantly, between directly unreachable DEVs within the same piconet, 3PHP has a much lower failure probability, and is up to 10 times faster than the standard method in establishing a peer-to-peer connection as the latter fails and network layer routing is invoked.

  • third party handshake protocol for efficient peer discovery in ieee 802 15 3 wpans
    Broadband Communications Networks and Systems, 2005
    Co-Authors: Victor C M Leung
    Abstract:

    Designed for high data rate wireless personal area networks (WPANs), the IEEE 802.15.3 medium access control (MAC) protocol fits well with emerging technologies such as ultra-wideband (UWB). In an 802.15.3 piconet, all MAC frames are exchanged in a peer-to-peer manner between devices (DEVs) to allow efficient ad hoc operations while the piconet coordinator (PNC) only provides timing synchronization in the piconet; thus peer discovery is an essential function. If two peer DEVs in a piconet are out of transmission range, the standard peer discovery method will fail, and a costly upper layer routing procedure is required to complete the peer connection. In this paper, we propose a third-party handshake protocol (3PHP) at the 802.15.3 MAC layer to provide reliable and prompt peer discovery between out of range DEVs in a piconet via the PNC. It removes the overhead of unsuccessful peer discovery in the standard method, and completely eliminates costly upper layer routing between these DEVs by means of a simple and efficient MAC layer PNC forwarding. The performance of the proposed scheme is evaluated by a novel CSMA/CA delay analysis for the contention access period (CAP). Analytical and simulation results show that for uniformly distributed DEVs over the maximum coverage of a piconet, up to 41.3% of intra-piconet peer discovery procedures may fail if the standard method is used. The cost of unsuccessful MAC peer discovery and consequent routing is very high. The expected peer discovery time for 3PHP is 100 mum lower than that of the standard method when the latter is successful in peer discovery, and up to 10 times faster than the standard method with network layer routing when the standard method is unsuccessful in connecting the peer DEVs. 3PHP also significantly reduces the peer discovery failure probability. Therefore, the proposed 3PHP scheme brings huge performance gain with minimum cost, and successfully resolves the potential connectivity issue in an IEEE 802.153 piconet

  • novel design of high capacity bluetooth access point with collision avoidance scheduling
    Personal Indoor and Mobile Radio Communications, 2004
    Co-Authors: Zhifeng Jiang, Victor C M Leung
    Abstract:

    Bluetooth access points (BAP) allow Bluetooth devices to access the Internet via wireline facilities. The capacity of a BAP is limited by the data rate and number of active slaves supported by each Bluetooth piconet. The paper presents a novel design of a high capacity BAP employing multiple transceivers to support several Piconets, and a common baseband processor implementing a collision avoidance scheduling (CAS) algorithm to minimize the detrimental effects of interference between collocated Piconets. Numerical results are presented to illustrate the effectiveness of the proposed CAS algorithm in increasing the throughput of the BAP compared to a BAP that does not employ CAS.

Chih-yung Chang - One of the best experts on this subject based on the ideXlab platform.

  • congestion control of bluetooth radio system by piconet restructuring
    Journal of Network and Computer Applications, 2008
    Co-Authors: Gwojong Yu, Chih-yung Chang
    Abstract:

    Bluetooth is a low-cost and short-range wireless communication technology. Two or more bluetooth devices connected form a piconet and two or more Piconets connected form a scatternet through relay devices. Without the consideration of traffic flows, a scatternet may operate with serious congestion problem. Congestion problem can be resolved by either reduced traffic flows or increased bandwidth provision. In bluetooth, new piconet can be dynamically constructed to increase system bandwidth. However, as the number of piconet is increased, collision problem among Piconets becomes a serious problem. The objective of this paper is to resolve the congestion problems in a scatternet through piconet restructuring which perform both flow analysis and distributed role-switching technique. Advantages of the proposed piconet restructuring mechanism includes the following: (1) the communication bottleneck can be released; (2) the communication path is shortened; (3) the transmission latency is reduced; and (4) the lifetime of Piconets can be increased. Experimental results demonstrated that the proposed method could effectively increase the transmission efficient in each piconet and increase the performance of an entire scatternet.

  • tarp a traffic aware restructuring protocol for bluetooth radio networks
    Computer Networks, 2007
    Co-Authors: Chih-yung Chang, Chao-tsun Chang
    Abstract:

    Bluetooth is a low-cost and short-range wireless communication technology. The Bluetooth device randomly searches and connects with other devices using the inquiry/inquiry scan and the page/page scan operations, resulting an uncontrolled scatternet topology. The unpredictable scatternet topology usually raises the problem of redundant traffic and causes inefficient communications. A traffic-aware restructuring protocol (TARP) is presented for partially restructuring a piconet or a pair of two neighboring Piconets by applying role switch mechanism. The proposed TARP mainly consists of intra-piconet and inter-piconet restructuring protocols. According to the recent routes and their traffic load information, the intra-piconet restructuring protocol adjusts piconet structure by selecting the proper device to play a master role of a piconet and applies takeover operation to rapidly restructure the piconet topology. The inter-piconet restructuring protocol exchanges devices of two neighboring Piconets to reduce the route length and thus improve the power and bandwidth consumptions and the end-to-end transmission delay. Performance results reveal that the proposed restructuring protocols reduce path length of recent routes and save power consumption, thus significantly improve the performance for a given connected scatternet.

  • relay reduction and disjoint routes construction for scatternet over bluetooth radio system
    Journal of Network and Computer Applications, 2007
    Co-Authors: Gwojong Yu, Chih-yung Chang, Kuei-ping Shih
    Abstract:

    Bluetooth is a new technology for low-cost, low-power, and short-range wireless communication. By constructing a piconet, Bluetooth device establishes link and communicates with other device in a master-slave manner. Relay is a Bluetooth device that joins two or more Piconets and forwards data from one piconet to another, providing multi-hop (or inter-piconet) communication services. In a Bluetooth scatternet, the number of relays and the degree of each relay are factors that significantly affect the performance of entire network. Unnecessary relays raise the difficulty of scheduling, leading to frequent packet loss. Relay switching among several Piconets in turns also creates guard time overhead and increases the transmission delay. This study presents an effective protocol that can dynamically adjust the network topology by reducing the unnecessary relays. An efficient scatternet environment thus can be constructed with characteristics of connected, high bandwidth utilization and low maintenance cost. Additionally, a routing protocol is developed to reduce the path length and generate two disjoint routes for any pair of source and destination devices located in different Piconets. Experimental results demonstrate that the proposed protocols perform well in terms of route length, bandwidth consumption, and transmission delay.

Duk Kyung Kim - One of the best experts on this subject based on the ideXlab platform.

  • enhanced ieee 802 15 3 mac protocol for efficient support of multiple simultaneously operating Piconets
    IEEE Transactions on Vehicular Technology, 2008
    Co-Authors: Peng Xue, Peng Gong, Duk Kyung Kim
    Abstract:

    The IEEE 802.15.3 medium access control (MAC) protocol is designed to support high-data-rate wireless personal area networks (WPANs). This protocol operates on a time-division multiple-access (TDMA) basis within a piconet, which guarantees interference-free connections. However, it is found that the protocol is not efficient for simultaneously operating Piconets (SOPs). In the current protocol, SOPs can be linked by a parent/child (P/C) or parent/neighbor (P/N) configuration for interference mitigation. However, the throughput is limited because the same superframe is shared by the P/C and P/N Piconets. In this paper, an adaptive channel time allocation (CTA) is proposed, including public and normal CTAs, to adaptively manage the interpiconet interference in SOPs. In a mobile environment, the public and normal CTAs can also be adaptively allocated based on the link status in the SOPs, thereby reducing interference and improving the efficiency of channel time usage. The proposed scheme is able to achieve a greater throughput than the P/C and P/N configurations. In addition, the link success probability can also be kept at a high value. Based on the SOPs of the direct-sequence ultrawideband (DS-UWB) system, the simulation results demonstrate that the proposed scheme effectively supports the coexistence of SOPs. Furthermore, it not only significantly improves the throughput of the SOPs but also maintains a high link success probability.

  • efficient management of multiple Piconets in an mc cdma based uwb system
    IEICE Transactions on Communications, 2008
    Co-Authors: Peng Gong, Peng Xue, Cheng Jie Piao, Duk Kyung Kim
    Abstract:

    With multiple overlapped Piconets, the IEEE 802.15.3 Medium Access Control (MAC) protocol uses a Parent/Child (P/C) or Parent/Neighbor (P/N) configuration to avoid inter-piconet interference. However, the throughput of a P/N or P/C configuration cannot exceed that of a single piconet. In the present paper we propose an efficient means of managing multiple Piconets to cooperate with a Multi-Carrier Code Division Multiple Access (MC-CDMA) based UWB system. The proposed management approach uses an Intermediate Device (IDEV) to connect Piconet Coordinators (PNCs). A senior PNC adaptively arranges two simultaneous data transmission links with the proposed spreading matrices in each Channel Time Allocation (CTA) instead of a P/C or P/N configuration, which supports only a single link in each CTA. Simulation results demonstrate the proposed scheme can achieve a higher throughput with an acceptable compromise of link success probability in multiple overlapped Piconets.

  • performance enhancement of ieee 802 15 3 mac for simultaneously operating Piconets
    The Journal of Korean Institute of Communications and Information Sciences, 2007
    Co-Authors: Xue Peng, Gong Peng, Duk Kyung Kim
    Abstract:

    In the IEEE 802.15.3 Medium Access Control (MAC) protocol, Simultaneously Operating Piconets (SOPs) are linked by the parent/child (P/C) or parent/neighbor (P/N) configuration, which work on a Time Division Multiple Access (TDMA) basis. This provides interference mitigation but the overall throughput is limited because the SOPs share the channel time exclusively. The protocol is not efficient for SOPs if we focus on the combination of interference mitigation and high throughput maintenance. In this paper Public Channel Time Allocation (Public CTA) is proposed, which is able to greatly reduce the inter-piconet interference (IPI) and achieve greater throughput without much loss of link success probability (LSP) in the SOPs. The simulation results based on the SOPs of Direct Sequence Ultra Wideband (DS-UWB) system demonstrate that the proposed scheme effectively supports the coexistence of SOPs, and it can not only significantly improve the overall throughput of SOPs but also maintain high LSP.

  • intelligent channel time allocation in simultaneously operating Piconets based on ieee 802 15 3 mac
    International Conference on Knowledge-Based and Intelligent Information and Engineering Systems, 2006
    Co-Authors: Peng Xue, Peng Gong, Duk Kyung Kim
    Abstract:

    The IEEE 802.15.3 Medium Access Control (MAC) protocol is designed to support low power and high rate Wireless Personal Area Networks (WPANs). It works on a Time Division Multiple Access (TDMA) basis within a piconet, which guarantees interference-free connections. However, the current protocol is not efficient for Simultaneously Operating Piconets (SOPs), which are linked by the parent/child (P/C) and parent/neighbor (P/N) relationships. It provides interference mitigation but the throughput is limited since the channel time is exclusively allocated. In this paper we propose Intelligent Channel Time Allocation (Intelligent CTA), which includes Public CTA and Normal CTA, to intelligently manage the inter-piconet interference (IPI). The proposed scheme is able to greatly reduce the IPI. Based on the DS-UWB system, the simulation results show that the proposed scheme can effectively support the coexistence of SOPs and it can achieve higher throughput without significant loss of link success probability (LSP) in the SOPs.

Xiangqian Liu - One of the best experts on this subject based on the ideXlab platform.

  • Collision Resolution for Robust Coexistence of Multiple Bluetooth Piconets
    2013
    Co-Authors: Xiangqian Liu
    Abstract:

    With the increasing popularity of wireless networking, multiple networks are likely to coexist in a physical environment. Without coordination among coexisting networks, interference due to frequency collision may greatly decrease the performance. For example, packet error rate can be as high as 20 % in a 12-piconet environment [1]. Most existing techniques focus on collision avoidance at the MAC layer, which are not applicable when there are multiple uncoordinated frequency hopping (FH) networks, such as multiple Bluetooth Piconets. Recently we developed a signal processing technique that resolves collisions in the physical layer, and recovers data packet without retransmission, thus improving network throughput

  • dual channel transmission for coexistence of bluetooth Piconets with multi slot packets
    International Symposium on Wireless Pervasive Computing, 2007
    Co-Authors: Xiangqian Liu
    Abstract:

    Coexistence has become an important problem with the increasing deployment of wireless networks in the unlicensed frequency band. Most collision avoidance schemes developed for the coexistence of Bluetooth and WLAN are not applicable to multiple coexisting Bluetooth Piconets due to constant frequency hopping. We propose a dual channel transmission (DCT) scheme to reduce the packet error rate (PER) due to channel collisions when multiple Bluetooth Piconets coexist. With DCT, the same packet is transmitted on two distinct frequency hopped channels simultaneously, and the power used in each channel is half of what would be used in single channel transmission (SCT). We analyze the performance for multiple Bluetooth Piconets with multi-slot packets in noisy environment. Performance analysis shows that compared to SCT, DCT can significantly reduce the PER when a small number of Piconets coexist, and thus the network throughput can be increased by using DCT.

  • evaluation of co channel and adjacent channel interference for multiple bluetooth Piconets with dual channel transmission
    Wireless Communications and Networking Conference, 2007
    Co-Authors: Xiangqian Liu
    Abstract:

    The paper proposed a frequency diversity technique for Bluetooth, namely dual channel transmission (DCT), to reduce the packet error rate (PER) due to inter-piconet interference when multiple Bluetooth Piconets coexist. With DCT, the same packet is transmitted on two distinct frequency hopped channels simultaneously, and the power used in each channel is half of what would be used in single channel transmission (SCT). A packet is successfully received if at least one channel survives. There is a tradeoff between the increased reliability due to the diversity offered by DCT, and the potentially increased interference due to the use of extra channel. The authors evaluate the performance of DCT when co-channel and adjacent channel interference, as well as wireless propagation characteristics are considered. It is shown that with DCT, the PER is significantly lower than that of SCT when a small number of Piconets coexist. Numerical simulations validate the analysis and demonstrate the effectiveness of DCT.

  • a collision resolution technique for robust coexistence of multiple bluetooth Piconets
    Vehicular Technology Conference, 2006
    Co-Authors: Xiangqian Liu
    Abstract:

    Frequency collision caused by coexistence has become a critical issue with the increasing deployment of wireless networks in the unlicensed frequency band. Most collision avoidance schemes developed for the coexistence of Bluetooth and WLAN are not applicable to multiple coexisting Bluetooth Piconets due to constant frequency hopping in Bluetooth. Relying on a blind hop timing and frequency estimation algorithm, in this paper we propose a collision resolution technique that resolves collided data packets without retransmission, thus enabling robust coexistence of multiple Bluetooth Piconets. Simulation results demonstrate the effectiveness of this technique.